1. Field of the Invention
The present invention relates to Trichoderma harzianum SK-55 fungus (which is deposited under No. 13327 and International deposit No. Ferm. BP 4346, at a patent microorganism depository, the National Institute of Bioscience and Human-Technology (NIBH), Japan) that provides a wide range of antagonism against fungal diseases in plants, whereby those plant diseases caused by fungi can be controlled. The present invention also provides a method of manufacturing fungicide that contains the Trichoderma harzianum SK-55 fungus, and the use of the same.
2. Description of the Prior Art
In the prior art, agricultural chemicals that contain chemical compounds synthesized chemically are generally used to control plant diseases caused by soil-borne pathogenic fungi. For those years, the demands for protecting the natural environment and conserving the natural resources are important, and it is more interesting to provide a biological fungicide that is not harmful to humans, animals or plants.
In this respect, fungi of the Tricoderma species are of particular interest because of their effective and useful control of the dense growth of fungi that is promoted by the lysis, biotrophic myco-parasite and competition of the fungi.
For example, it is recognized that the fungi of the Tricoderma species may provide the fungicide effect if their conidia or chlamydospores or the antagonistic microorganism in their extractions are utilized (Japan unexamined patent publication No. 1-102010).
It is also reported that an aqueous Tricoderma sp. -35/84 spore suspension can advantageously be used for controlling the Pythium fungi in particular (Japan unexamined patent publication No. 2-245178). Furthermore, it is reported that the Tricoderma harzianum T315 fungus has resistance to chemical fungicides, and may provide higher fungicidal control against more kinds of fungi when it is combined with any other chemical fungicides (European patient specification No. 0133 878 B1).
Those kinds of fungi which have been reported as providing the antifungal activity as mentioned above are disadvantageous because they are not economical for practical use, have limited capability of controlling the plant diseases caused by fungi, and may cause environmental pollution or harm to humans, animals, plants, etc.
It is known that 80% of the plant diseases are caused by the soil-borne pathogetic fungi. It might therefore be possible to control such fungal diseases by preventing the growth of the pathogenic fungi more effectively, but there are many cases where in this way, the symptoms of the diseases caused by those kinds of pathogenic fungi which are usually identified as the sources of the diseases cannot appear even if a host is inoculated with those pathogenic fungi. This is principally because the appearance of the disease symptom is associated with the interaction of the particular fungi (which applies particularly to lawns). For practical purposes, the antifungal control may be achieved by using any suitable chemicals that provide a broad range of antifungal action.
The above observation applies similarly to biological control which has similar problems and cannot be utilized for practical purposes. Those problems lie in the selection of any strains that provide the broad antagonistic interaction, the high settlement of such strains in the soil and plant root, and the growth of mycelia which cannot be influentially controlled by any external factors.